Replacement prosthetic heart valves

ABSTRACT

A two-stage or component-based valve prosthesis that can be quickly and easily implanted during a surgical procedure is provided. The prosthetic valve comprises a support structure that is deployed at a treatment site. The prosthetic valve further comprises a valve member configured to be quickly connected to the support structure. The support structure may take the form of a stent that is expanded at the site of a native valve. If desired, the native leaflets may remain and the stent may be used to hold the native valve open. In this case, the stent may be balloon expandable and configured to resist the powerful recoil force of the native leaflets. The support structure is provided with a coupling means for attachment to the valve member, thereby fixing the position of the valve member in the body. The valve member may be a non-expandable type, or may be expandable from a compressed state to an expanded state. The system is particularly suited for rapid deployment of heart valves in a conventional open-heart surgical environment.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/571,141, filed Dec. 15, 2014, now U.S. Pat. No. 9,554,903, which is acontinuation of U.S. patent application Ser. No. 13/954,822, filed Jul.30, 2013, now U.S. Pat. No. 8,911,493, which is a continuation of U.S.patent application Ser. No. 11/441,406, filed May 24, 2006, now U.S.Pat. No. 8,500,798, which claims priority to Provisional Application No.60/684,443, filed on May 24, 2005, entitled “Prosthetic Valve forImplantation in a Body Channel.”

FIELD OF THE INVENTION

The present invention generally relates to prosthetic valves forimplantation in body channels. More particularly, the present inventionrelates to prosthetic heart valves configured to be surgically implantedin less time than current valves.

BACKGROUND OF THE INVENTION

Due to aortic stenosis and other heart valve diseases, thousands ofpatients undergo surgery each year wherein the defective native heartvalve is replaced by a prosthetic valve, either bioprosthetic ormechanical. When the valve is replaced, surgical implantation of theprosthetic valve typically requires an open-chest surgery during whichthe heart is stopped and patient placed on cardiopulmonary bypass (aso-called “heart-lung machine”). In one common surgical procedure, thediseased native valve leaflets are excised and a prosthetic valve issutured to the surrounding tissue at the valve annulus. Because of thetrauma associated with the procedure and the attendant duration ofextracorporeal blood circulation, some patients do not survive thesurgical procedure or die shortly thereafter. It is well known that therisk to the patient increases with the amount of time required onextracorporeal circulation. Due to these risks, a substantial number ofpatients with defective valves are deemed inoperable because theircondition is too frail to withstand the procedure. By some estimates,about 30 to 50% of the subjects suffering from aortic stenosis who areolder than 80 years cannot be operated on for aortic valve replacement.

Because of the drawbacks associated with conventional open-heartsurgery, percutaneous and minimally-invasive surgical approaches aregarnering intense attention. In one technique, a prosthetic valve isconfigured to be implanted in a much less invasive procedure by way ofcatheterization. For instance, U.S. Pat. No. 5,411,552 to Andersen etal. describes a collapsible valve percutaneously introduced in acompressed state through a catheter and expanded in the desired positionby balloon inflation. Although these remote implantation techniques haveshown great promise for treating certain patients, replacing a valve viasurgical intervention is still the preferred treatment procedure. Onehurdle to the acceptance of remote implantation is resistance fromdoctors who are understandably anxious about converting from aneffective, if imperfect, regimen to a novel approach that promises greatoutcomes but is relatively foreign. In conjunction with theunderstandable caution exercised by surgeons in switching to newregimens of heart valve replacement, regulatory bodies around the worldare moving slowly as well. Numerous successful clinical trials andfollow-up studies are in process, but much more experience with thesenew technologies will be required before they are completely accepted.One question that remains unanswered is whether the new expandablevalves will have the same durability as conventional prosthetic heartvalves.

Accordingly, there is a need for an improved device and associatedmethod of use wherein a prosthetic valve can be surgically implanted ina body channel in a more efficient procedure that reduces the timerequired on extracorporeal circulation. It is desirable that such adevice and method be capable of helping patients with defective valvesthat are deemed inoperable because their condition is too frail towithstand a lengthy conventional surgical procedure. The presentinvention addresses this need.

SUMMARY OF THE INVENTION

Various embodiments of the present invention provide prosthetic valvesand methods of use for replacing a defective native valve in a humanheart. Certain embodiments are particularly well adapted for use in asurgical procedure for quickly and easily replacing a heart valve whileminimizing time using extracorporeal circulation (i.e., bypass pump).

In one embodiment, a method for treating a native aortic valve in ahuman heart, comprises: 1) accessing a native valve through an openingin a chest; 2) advancing an expandable support structure to the site ofa native aortic valve, the support structure being radially compressedduring the advancement; 3) radially expanding the support structure atthe site of the native aortic valve; and 4) mechanically coupling avalve member to the expanded support structure, wherein the valve memberreplaces the function of the native aortic valve. A furtherunderstanding of the nature and advantages of the present invention areset forth in the following description and claims, particularly whenconsidered in conjunction with the accompanying drawings in which likeparts bear like reference numerals.

In one variation, the support structure is a stent, which may comprise ametallic frame. In one embodiment, at least a portion of the metallicframe is made of stainless steel. In another embodiment, at least aportion of the metallic frame is made of a shape memory material. Thevalve member may take a variety of forms. In one preferred embodiment,the valve member comprises biological tissue. The valve member furthercomprises a coupling portion configured to be connected to the supportstructure in a quick and efficient manner. In another variation of thismethod, the metallic frame is viewed under fluoroscopy duringadvancement of the prosthetic valve toward the native aortic valve.

The native valve leaflets may be removed before delivering theprosthetic valve. Alternatively, the native leaflets may be left inplace to reduce surgery time and to provide a stable base for fixing thesupport structure within the native valve. In one advantage of thismethod, the native leaflets recoil inward to enhance the fixation of themetallic frame in the body channel. When the native leaflets are left inplace, a balloon or other expansion member may be used to push the valveleaflets out of the way and thereby dilate the native valve beforeimplantation of the support structure.

In another preferred embodiment, a method for treating a native aorticvalve in a human heart, comprises accessing a native valve through anopening in a chest; advancing an expandable member to a position withinthe native aortic valve, the native aortic valve having at least twovalvular leaflets; dilating the native aortic valve by expanding theexpandable member to push aside the valvular leaflets of the nativeaortic valve; collapsing the expandable member and withdrawing theexpandable member from the native aortic valve; advancing an expandablesupport structure to a position within the dilated native aortic valve,the support structure being radially compressed during the advancement;radially expanding the support structure within the dilated aorticvalve, wherein the expanded support structure maintains the nativeaortic valve in the dilated condition; and coupling a valve member tothe expanded support structure, wherein the valve member replaces thefunction of the native aortic valve.

In another aspect, an improved prosthetic valve comprises an expandablestent sized for implantation at the site of a native aortic valve, thestent having a coupling means (e.g., a plurality of tines extending froma first end thereof); and a valve member comprising three leafletsmounted on a base portion. The coupling means is configured forattachment to the valve member. Alternatively, the coupling means may beprovided on the valve member or on both the stent and valve member.

A particularly useful configuration of the present invention is atwo-stage prosthetic heart valve, comprising an expandable anchoringmember sized to contact a heart valve annulus in an expanded state and asubstantially non-expandable valve member configured for connection tothe anchoring member. Desirably, the valve member includes a base ringsurrounding an inflow end thereof, and the anchoring member comprises atubular structure having connectors adapted to engage the base ring. Theconnectors may comprise prongs that change shape and engage the basering. For example, the base ring may be made of a suture-permeablematerial, and the prongs are configured to pierce the base ring, or theprongs are shaped to wrap around the base ring.

In an exemplary embodiment, the valve member includes a plurality ofdiscrete connectors spaced around a peripheral inflow end thereof, andthe anchoring member comprises a tubular structure having a plurality ofmating connectors spaced around a peripheral outflow end thereof. Theconnectors on the valve member and anchoring member engage one anotherby displacing the valve member toward the anchoring member. Forinstance, the connectors on either the valve member or anchoring membercomprise latches, and the connectors on the other of the valve member oranchoring member comprise brackets, the latches configured to engage andlock to the brackets upon axial movement of the latches and bracketstoward one another. Additionally, a plurality of guide filaments may beprovided, at least one for each of the connectors on the anchoringmember and slidingly received by the associated connector on the valvemember. The guide filaments guide the valve member in proper orientationwith respect to the anchoring member to ensure engagement of the matingconnectors.

Desirably, the anchoring member comprises a stent having a wider outflowend than an inflow end thereof, wherein the valve member comprises abase ring surrounding an inflow end thereof that fits within the outflowend of the stent. In one embodiment, the valve member includes asuture-permeable base ring surrounding an inflow end thereof, and theanchoring member comprises a tubular structure having a suture-permeablefixation ring attached thereto, wherein the valve member connects to theanchoring member via sutures looped between the base ring and thefixation ring.

Another embodiment of the present invention comprises a two-stageprosthetic heart valve, having an expandable anchoring member sized tocontact a heart valve annulus in an expanded state, a valve member, andan adapter sized to surround the valve member and engage the anchoringmember, to connect the valve member and anchoring member. The adaptermay be an annular ring or a wireform-shaped member that closelysurrounds and conforms to cusps and commissures of a flexible leafletvalve member.

Whatever its shape, the adapter desirably includes a plurality ofdiscrete connectors, and the anchoring member comprises a tubularstructure having a plurality of mating connectors spaced around aperipheral outflow end thereof. The connectors on the adapter andanchoring member are configured to engage one another by displacing theadapter toward the anchoring member. For example, the connectors oneither the adapter or anchoring member comprise latches, and theconnectors on the other of the adapter or anchoring member comprisebrackets, the latches being configured to engage and lock to thebrackets upon axial movement of the latches and brackets toward oneanother. In addition, the valve member preferably has a base ringsurrounding an inflow end thereof, and the adapter further includes aplurality of connectors adapted to engage and couple the adapterdirectly to the base ring.

Another aspect of the present invention is a system for retrofitting aconventional prosthetic heart valve, comprising an off-the-shelf,non-expandable prosthetic heart valve having a sewing ring capable ofbeing implanted using sutures through the sewing ring in an open-heartprocedure. An expandable anchoring member contacts and anchors to aheart valve annulus in an expanded state. Coupling means connects theprosthetic heart valve to the anchoring member, the prosthetic heartvalve thus being attached to the heart valve annulus via the anchoringmember.

In the system for retrofitting a conventional prosthetic heart valve,the anchoring member may comprise a tubular structure having asuture-permeable fixation ring attached thereto, wherein the couplingmeans comprises sutures looped between the base ring and the fixationring. An adapter sized to surround the heart valve engages the anchoringmember, to connect the heart valve and anchoring member. The adapter maybe annular or wireform-shaped. Desirably, the adapter includes aplurality of discrete connectors, and the anchoring member comprises atubular structure having a plurality of mating connectors spaced arounda peripheral outflow end thereof, the connectors on the adapter andanchoring member being configured to engage one another by displacingthe adapter toward the anchoring member.

A surgical method of implanting a prosthetic heart valve of the presentinvention in a patient involves providing a two-stage prosthetic heartvalve comprising an expandable anchoring member and a valve member, theanchoring member being sized to contact a heart valve annulus in anexpanded state and the valve member being configured to connect to theanchoring member. The patient is prepared for surgery by placing him/heron cardiopulmonary bypass. The surgeon creates a direct access pathwayto the heart valve annulus that preferably permits direct (i.e., nakedeye) visualization of the heart valve annulus. The anchoring member isdelivered and expanded to contact the valve annulus, and the valvemember is delivered and connected to the anchoring member. Preferably,the direct access pathway is created by performing open-heart surgery.The method may include balloon-expanding the anchoring member. Further,the valve member may be expandable and the method includes deliveringthe valve member in a compressed state and expanding it prior toconnecting it to the anchoring member.

In one embodiment, the valve member and the anchoring member areprovided with mating connectors, and the step of delivering andconnecting the valve member to the anchoring member comprises axiallydisplacing the valve member toward the anchoring member so that themating connectors engage. In another embodiment, the anchoring membercomprises a stent having an outflow end larger than an inflow endthereof, and the valve member comprises a non-expandable valve memberhaving a base ring on an inflow end thereof sized to fit within theoutflow end of the stent. The anchoring member may be provided withbendable connectors on an outflow end thereof, and the method includescausing the connectors to bend inward and engage a peripheral base ringof the valve member. For example, a bending tool may be used to bendconnectors inward.

Another surgical method of implanting a two-stage prosthetic heart valvein a patient of the present invention includes providing an expandableanchoring member sized to contact a heart valve annulus in an expandedstate, delivering and attaching the anchoring member to the heart valveannulus, providing a non-expandable valve member, and delivering andconnecting the valve member to the anchoring member. The valve memberand the anchoring member may be provided with mating connectors, and thestep of delivering and connecting the valve member to the anchoringmember comprises axially displacing the valve member toward theanchoring member so that the mating connectors engage. Desirably, theanchoring member comprises a stent having an outflow end larger than aninflow end thereof, and wherein the valve member comprises a base ringon an inflow end thereof sized to fit within the outflow end of thestent. The anchoring member may be provided with bendable connectors onan outflow end thereof, and the method includes causing the connectorsto bend inward and engage a peripheral base ring of the valve member,such as by using a bending tool.

In an exemplary embodiment, the valve member includes a base ring on aninflow end thereof, and the method further includes providing an adaptersized to surround the valve member and seat on the base ring. The methodtherefore includes the step of delivering and connecting the valvemember and coupling the adapter to the anchoring member. For instance,the adapter includes a plurality of discrete connectors, and theanchoring member comprises a tubular structure having a plurality ofmating connectors spaced around a peripheral outflow end thereof. Thestep of coupling the adapter to the anchoring member comprisesdisplacing the adapter toward the anchoring member to engage the matingconnectors thereon. Additionally, the adapter may further have aplurality of connectors adapted to engage and couple the adapterdirectly to the base ring, and the method includes causing theconnectors to engage the base ring.

In a still further surgical method of implanting a prosthetic heartvalve in a patient, a prosthetic heart valve and a separate expandableanchoring member are provided. The prosthetic heart valve and anchoringmember are positioned within a valve dilator/delivery tube having anexterior diameter sized to dilate a heart valve annulus. The valvedilator/delivery tube advances to the heart valve annulus, and theannulus is dilated using the valve dilator/delivery tube. The anchoringmember is expulsed from the tube and expanded to contact the heart valveannulus. The prosthetic heart valve is then expulsed from the valvedilator/delivery tube, and connected to the anchoring member.

Another method of the present invention comprises retrofitting andrapidly implanting a conventional prosthetic heart valve in a patient.The method includes providing an off-the-shelf non-expandable prostheticheart valve having a sewing ring capable of being implanted usingsutures through the sewing ring in an open-heart procedure. Anexpandable tissue anchoring member sized to contact a heart valveannulus in an expanded state is delivered and expanded into contact withthe heart valve annulus. Finally, the prosthetic heart valve isdelivered and connected to the tissue anchoring member.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained and other advantages and featureswill appear with reference to the accompanying schematical drawingswherein:

FIG. 1 is an exploded perspective view illustrating a preferredembodiment of a two-stage prosthetic valve comprising a stent portionand a valve member, wherein the valve member may be quickly and easilyconnected to the stent portion.

FIG. 2 illustrates the valve embodiment of FIG. 1 after the valve memberhas been attached to the stent portion by crimping portions of the stentover the commissural points of the valve member.

FIG. 3 is an exploded perspective view of an alternative embodimentwherein the stent is provided with a plurality of tines configured to becrimped to a ring along the base of the valve member.

FIG. 4 illustrates the valve embodiment of FIG. 3 after the valve memberhas been attached to the stent portion by crimping the tines on to thevalve member.

FIG. 4A is a sectional view through one side of the prosthetic heartvalve of FIG. 4 taken along line 4A-4A and showing one configuration oftines connecting through a sewing ring portion of the valve member.

FIG. 5 is an exploded perspective view of an alternative embodimentwherein slotted posts are provided on the stent for coupling toprotruding members on the valve member.

FIG. 5A is an enlarged view of one of the slotted posts provided on thestent of FIG. 5.

FIGS. 6 and 6A illustrate another alternative embodiment similar toFIGS. 5 and 5A wherein the posts are configured with L-shaped slots forlocking the valve member to the stent.

FIG. 7 is a sectional view through a body channel that illustrates analternative embodiment of prosthetic heart valves wherein first andsecond stents are provided for anchoring a valve member within the bodychannel.

FIG. 8 is an exploded perspective view of an alternative embodimentwherein the stent has a small diameter and a large diameter and whereinan expandable valve member is deployed within the large diameter.

FIG. 9A is an exploded perspective view of another alternativeembodiment of a two part prosthetic valve wherein a ring portion alongthe base of the valve member snaps into a groove formed in the stent.

FIG. 9B illustrates the embodiment of FIG. 9A with the valve memberconnected to the stent.

FIG. 10 is an exploded perspective view of another alternativeembodiment wherein the valve member and the stent are provided withcorresponding threaded portions for threadably engaging the valve memberto the stent.

FIG. 11 is an exploded perspective view of an alternative prostheticheart valve of the present invention having a valve member, stent, and athreaded locking ring for coupling the two together.

FIGS. 12A and 12B are exploded and assembled perspective views of analternative two-stage prosthetic heart valve having a valve member andtubular, expandable stent with tabs on an outflow end for coupling tothe valve member.

FIGS. 12C and 12D are sectional views through one side of the prostheticheart valve of FIG. 12B schematically illustrating an exemplary toolthat may be used to bend the tabs on the outflow end of the stent arounda sewing ring of the valve member.

FIGS. 13A and 13B are exploded and assembled perspective views of analternative prosthetic heart valve of the present invention wherein avalve member and stent with tabs are coupled together in conjunctionwith a locking ring.

FIGS. 14A and 14B are exploded and assembled perspective views of astill further prosthetic heart valve wherein a valve member and tubular,expandable stent are coupled together using a wireform-shaped adapterhaving tabs.

FIGS. 15A and 15B are exploded and assembled perspective views of aprosthetic heart valve having a valve member and stent with lockingbands on an outflow end.

FIGS. 16A and 16B are exploded and assembled perspective views of analternative prosthetic heart valve wherein a stent exhibits lockingclips on an outflow end that are guided through mating slits on alocking ring to join the stent to a valve member.

FIGS. 17A and 17B are exploded and assembled perspective views of analternative prosthetic heart valve wherein a stent has brackets on anoutflow end that receive guided locking clips on a locking ring to jointhe stent to a valve member.

FIG. 18 is a perspective view of an alternative stent for use in aprosthetic heart valve of the present invention.

FIG. 19 is a detailed sectional view through an inflow side of aprosthetic heart valve utilizing the stent of FIG. 18 and showing avalve member base ring captured between two sets of prongs.

FIG. 20 is a perspective exploded view of a prosthetic heart valvehaving a tubular stent with upstanding tines and a valve member with anadditional adapter ring arranged around a base ring.

FIG. 21 is an exploded perspective view of an exemplary prosthetic heartvalve having an expandable stent and non-expandable valve memberconnected by an array of parachute sutures being removed from a storagejar.

FIGS. 22A-22C are several views of the implantation of the prostheticheart valve of FIG. 21 assisted by a tubular valve dilator/deliverytube.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention attempts to overcome drawbacks associated withconventional, open-heart surgery, while also adopting some of thetechniques of newer technologies which decrease the duration of thetreatment procedure. The prosthetic heart valves of the presentinvention are primarily intended to be delivered and implanted usingconventional surgical techniques, including the aforementionedopen-heart surgery. There are a number of approaches in such surgeries,all of which result in the formation of a direct access pathway to theparticular heart valve annulus. For clarification, a direct accesspathway is one that permits direct (i.e., naked eye) visualization ofthe heart valve annulus. In addition, it will be recognized thatembodiments of the two-stage prosthetic heart valves described hereinmay also be configured for delivery using percutaneous approaches, andthose minimally-invasive surgical approaches that require remoteimplantation of the valve using indirect visualization.

One primary aspect of the present invention is a two-stage prostheticheart valve wherein the tasks of implanting a tissue anchor and a valvemember are somewhat separated and certain advantages result. Forexample, a two-stage prosthetic heart valve of the present invention mayhave an expandable tissue anchoring member that is secured in theappropriate location using a balloon or other expansion technique. Avalve member is then coupled to the tissue anchoring member in aseparate or sequential operation. By utilizing an expandable anchoringmember, the duration of the initial anchoring operation is greatlyreduced as compared with a conventional sewing procedure utilizing anarray of sutures. The expandable anchoring member may simply be radiallyexpanded outward into contact with the implantation site, or may beprovided with additional anchoring means, such as barbs. The operationmay be carried out using a conventional open-heart approach andcardiopulmonary bypass. In one advantageous feature, the time on bypassis greatly reduced due to the relative speed of implanting theexpandable anchoring member.

For definitional purposes, the term “tissue anchoring member,” or simply“anchoring member” refers to a structural component of a heart valvethat is capable of attaching to tissue of a heart valve annulus. Theanchoring members described herein are most typically tubular stents, orstents having varying diameters. A stent is normally formed of abiocompatible metal wire frame, such as stainless steel or Nitinol.Other anchoring members that could be used with valves of the presentinvention include rigid rings, spirally-wound tubes, and other suchtubes that fit tightly within a valve annulus and define an orificetherethrough for the passage of blood, or within which a valve member ismounted. It is entirely conceivable, however, that the anchoring membercould be separate clamps or hooks that do not define a continuousperiphery. Although such devices sacrifice some dynamic stability, thesedevices can be configured to work well in conjunction with a particularvalve member.

The term “valve member” refers to that component of a heart valve thatpossesses the fluid occluding surfaces to prevent blood flow in onedirection while permitting it in another. As mentioned above, variousconstructions of valve numbers are available, including those withflexible leaflets and those with rigid leaflets or a ball and cagearrangement. The leaflets may be bioprosthetic, synthetic, or metallic.

A primary focus of the present invention is the two-stage prostheticheart valve having a first stage in which an anchoring member secures toa valve annulus, and a subsequent second stage in which a valve memberconnects to the anchoring member. It should be noted that these stagescan be done almost simultaneously, such as if the two components weremounted on the same delivery device, or can be done in two separateclinical steps, with the anchoring member deployed using a firstdelivery device, and then the valve member using another deliverydevice. It should also be noted that the term “two-stage” does notnecessarily limit the valve to just two parts, as will be seen below.

Another potential benefit of a two-stage prosthetic heart valve,including an anchoring member and a valve member, is that the valvemember may be replaced after implantation without replacing theanchoring member. That is, an easily detachable means for coupling thevalve member and anchoring member may be used that permits a new valvemember to be implanted with relative ease. Various configurations forcoupling the valve member and anchoring member are described herein.

It should be understood, therefore, that certain benefits of theinvention are independent of whether the anchoring member or valvemember are expandable or not. That is, various embodiments illustrate anexpandable anchoring member coupled to a conventional valve member.However, the same coupling structure may be utilized for anon-expandable anchoring member and conventional valve member.Additionally, although a primary embodiment of the present invention isan expandable anchoring member coupled with a conventional valve member,both could be expandable and introduced percutaneously or through aminimally-invasive approach. Therefore, the invention should not beconstrued as being limited in these regards, but instead should beinterpreted via the appended claims.

As a point of further definition, the term “expandable” is used hereinto refer to a component of the heart valve capable of expanding from afirst, delivery diameter to a second, implantation diameter. Anexpandable structure, therefore, does not mean one that might undergoslight expansion from a rise in temperature, or other such incidentalcause. Conversely, “non-expandable” should not be interpreted to meancompletely rigid or a dimensionally stable, as some slight expansion ofconventional “non-expandable” heart valves, for example, may beobserved.

In the description that follows, the term “body channel” is used todefine a blood conduit or vessel within the body. Of course, theparticular application of the prosthetic heart valve determines the bodychannel at issue. An aortic valve replacement, for example, would beimplanted in, or adjacent to, the aortic annulus. Likewise, a mitralvalve replacement will be implanted at the mitral annulus. Certainfeatures of the present invention are particularly advantageous for oneimplantation site or the other. However, unless the combination isstructurally impossible, or excluded by claim language, any of the heartvalve embodiments described herein could be implanted in any bodychannel.

With reference now to FIG. 1, one preferred embodiment of an improvedprosthetic valve 10 generally includes an expandable anchoring member orstent 20 and a valve member 30. The stent provides a support structurefor anchoring the valve member within a body lumen. Although a stent isdescribed for purposes of illustration, any support structure capable ofanchoring the valve member to the body lumen may be used. As will bedescribed in more detail below, the prosthetic valve is configured suchthat the valve member may be quickly and easily connected to the stent.It should be noted here, that the anchoring members or stents describedherein can be a variety of designs, including having the diamond-shapedopenings shown or other configurations detailed below. The materialdepends on the mode of delivery (i.e., balloon- or self-expanding), andthe stent can be bare strut material or covered to promote in-growthand/or to reduce paravalvular leakage. For example, a suitable coverthat is often used is a sleeve of fabric such as Dacron.

The stent may be securely deployed in the body channel using anexpandable member, such as, for example, a balloon. Because the stent isexpanded before the valve member is attached, the valve member will notbe damaged or otherwise adversely affected during the stent deployment.After the stent has been deployed in the body channel, the valve membermay be connected to the stent. In one preferred application, thetwo-stage prosthetic valve is well-suited for use in heart valvereplacement. In this application, the stent may be advantageously usedto push the native leaflets aside such that the valve member can replacethe function of the native valve. The anchoring members or stentsdescribed herein could include barbs or other such tissue anchors tofurther secure the stent to the tissue. In one preferred embodiment, thebarbs are deployable (e.g., configured to extend or be pushed radiallyoutward) by the expansion of a balloon.

In another advantageous feature, the two-stage prosthetic valveillustrated in FIG. 1 provides a device and method for substantiallyreducing the time of the surgical procedure. This reduces the timerequired on extracorporeal circulation and thereby substantially reducesthe risk to the patient. The surgical time is reduced because the stentmay be deployed quickly and the valve member may be attached to thestent quickly. This simplifies and reduces the surgical time as comparedwith replacement valves that are sutured to the tissue after removingthe native leaflets.

When used for aortic valve replacement, the valve member 30 preferablyhas three leaflets 36 which provide the valvular function for replacingthe function of the native valve. In various preferred embodiments, thevalve leaflets may be taken from another human heart (cadaver), a cow(bovine), a pig (porcine valve) or a horse (equine). In other preferredvariations, the valve member may comprise mechanical components ratherthan biological tissue. In one preferred embodiment, the valve iscompressible in diameter. Accordingly, the valve may be reduced indiameter for delivery into the stent and then expanded. The threeleaflets are supported by three commissural posts 34. A ring 32 isprovided along the base portion of the valve member.

With continued reference to FIG. 1, the stent 20 is provided with twodiameters. A lower portion 22 has a small diameter and an upper portion24 has a large diameter. The lower portion 22 is preferably sized to bedeployed at the location of the native valve (e.g., along the aorticannulus). The upper portion 24 expands outwardly into the perspectivecavity adjacent the native valve. For example, in an aortic valvereplacement, the upper portion 24 expands into the area of the sinuscavities just downstream from the aortic annulus. Of course, care shouldbe taken to orient the stent 20 so as not to block the coronaryopenings. The stent body is preferably configured with sufficient radialstrength for pushing aside the native leaflets and holding the nativeleaflets open in a dilated condition. The native leaflets provide astable base for holding the stent, thereby helping to securely anchorthe stent in the body. To further secure the stent to the surroundingtissue, the lower portion may be configured with anchoring members, suchas, for example, hooks or barbs (not shown).

The upper portion 24 of the stent 20 has a larger diameter sized forreceiving the valve member 30. A transition region 28 between the upperand lower portions of the stent body may be advantageously used toprovide a seat for the bottom end of the valve member. The stent mayfurther comprise a ridge (not shown) along an inner wall for providing amore definite seat portion within the stent.

With continued reference to FIG. 1, the prosthetic valve 10 is providedwith a coupling mechanism for securing the valve member 30 to the stent20. The coupling mechanism may take a variety of different forms.However, in the illustrated embodiment, the stent body comprises threeposts 26 which correspond to the three commissural points 34 on thevalve member. The three posts 26 are preferably formed of a malleablematerial such that the posts 26 may be crimped over the commissuralpoints on the valve member. A bending tool (not shown) may be providedfor crimping the posts 26 over the commissures of the valve member, orthe posts 26 may be hinged or made of the shape memory material so as tocurl once implanted in the body. With reference to FIG. 2, theprosthetic valve 10 is illustrated in the assembled condition with theposts 26 crimped over the commissural points 34 of the valve member. Inone variation, the three posts on the stent are formed with a recess forreceiving the commissural points, such as in a snap-fit relationship.

In a preferred embodiment, the stent 20 is expandable, but the valvemember 30 is a conventional, non-expandable prosthetic heart valve, suchas the Carpentier-Edwards PERIMOUNT Magna® Aortic Heart Valve availablefrom Edwards Lifesciences of Irvine, Calif. In this sense, a“conventional” prosthetic heart valve is an off-the-shelf (i.e.,suitable for stand-alone sale and use) non-expandable prosthetic heartvalve having a sewing ring capable of being implanted using suturesthrough the sewing ring in an open-heart procedure. An implant proceduretherefore involves first delivering and expanding the stent 20 and theaortic annulus, and then coupling the valve member 30 thereto. Becausethe valve member 30 is non-expandable, the entire procedure is typicallydone using the conventional open-heart technique. However, because thestent 20 is delivered and implanted by simple expansion, the entireoperation takes less time. This hybrid approach will also be much morecomfortable to surgeons familiar with the open-heart procedures andconventional heart valves. Moreover, the relatively small change inprocedure coupled with the use of proven heart valves should create amuch easier regulatory path than strictly expandable, remote procedures.

A variation of the embodiment described in FIGS. 1 and 2 may incorporatean expandable stent 20 and an expandable valve member 30. Although notshown, the valve member 30 may be capable of expansion within the body,such as the Cribier-Edwards Aortic Percutaneous Heart Valve, alsoavailable from Edwards Lifesciences. Therefore, the valve 10 may beimplanted without an open-heart procedure, and even without stoppingheart. In such a remote procedure, the three posts 26 on the stent 20may be made of a shape memory material having a temperature-inducedshape change once implanted. Alternatively, a tool for bending the posts26 may be delivered along with the valve 10 and utilized when the valvemember 30 seats within the stent 20.

With reference now to FIG. 3, an alternative prosthetic valve 10Acomprises a stent 40 provided with a bottom portion 42 and an upperflared portion 44. A plurality of prongs or tines 46 is disposed along atop end of the flared portion 44. The tines 46 are preferably bendablemembers configured to engage the ring portion 32 along the base of thevalve member 30. In one preferred embodiment, the tines 46 are crimpedover the ring as shown in FIG. 4. If desired, the tines 46 may havepointed tips for passing through a fabric or other similar materialalong the ring portion of the valve member, such as seen in FIG. 4A.

Once again, the stent 40 is desirably an expandable member that can beeasily delivered and implanted at the body channel. The valve member 30may be conventional, or may also be expandable. The illustratedembodiment shows a conventional valve 30 having the sewing ring portion32 surrounding an inflow end. Sewing rings are typically made ofsuture-permeable material covered with cloth. The tines 46 may be sharpenough to pierce the material of the sewing ring portion 32 (FIG. 4A).In this regard, a conventional valve member 30 may be utilized withoutmodification. In the alternative, the sewing ring portion 30 may bereplaced with a more rigid peripheral band or ring, and the tines 46 aresimply bent inward so as to fold over the ring and capture the valvemember 31 on the top of the stent 40. Desirably, a seat or rim of somesort is provided within the interior of the stent 40 so that the valvemember 30 can easily be positioned therein. The tines 46 may bemechanically bent using a deployment tool (not shown), or they may behinged or made of a shape memory material so as to curl inward uponreaching a certain temperature.

With reference now to FIG. 5, another alternative prosthetic valve 10Bcomprises an anchoring member or stent 50 provided with a cylindricalportion 52 and three posts 54 extending upward from the cylindricalportion. Each post 54 may be slotted, as illustrated in the enlargedview of FIG. 5B, or formed with an orifice. Radially protruding members38 are provided along the ring portion 32 of the valve member 30 formating with the posts on the stent. The exemplary slot has a thin neckportion 58 wherein engagement members, such as angled teeth, areprovided. The teeth are angled such that the slot widens as theprotruding member 38 is pushed downward into the slot. After passingthrough the teeth into the capture portion 59, the protruding member 38is securely captured. Because the teeth are angled in only onedirection, an upward force will not cause the slot to widen, therebycapturing the protruding member.

With reference now to FIG. 6, yet another alternative embodiment of acomponent prosthetic valve 10C is illustrated. The embodiment of FIG. 6is similar to the embodiment illustrated and described above withrespect to FIG. 5. However, in this variation, the posts or connectingmembers 55 are provided with L-shaped slots 57 for receiving theprotruding member disposed along the valve member. With reference toFIG. 6A, an enlarged view of one preferred connecting member 55 isshown. The slot 57 of the connecting member 55 is shaped such that theprotruding member 38 moves longitudinally into the slot and thenrotationally to enter the capture portion. One or more teeth 58 may beprovided for holding the protruding member in the capture portion.Alternatively, the protruding member 38 may be held in the slot 57 usingfriction or a mechanical locking member. In another alternative, a keylock system or “bayonet” attachment mechanism may be provided forcoupling the valve member to the stent.

With reference now to FIG. 7, another alternative prosthetic valve 10Dis illustrated wherein the valve member 30 is captured and held betweenfirst and second stents 60, 62. In use, the first stent 60 is expandedwithin a body channel such that the outer surface of the stent is incontact with the vessel wall 64. The valve member 30 is then advancedthrough the body channel and into contact with the first stent. A ring32 is preferably provided along the base portion of the valve member forcontacting the outflow end of the first stent. The second stent is thenadvanced through the body channel and is deployed such that an inflowend of the second stent contacts a top surface of the ring 32 of thevalve member for anchoring the valve member between the first and secondstents.

The embodiment of FIG. 7 employs a slightly different means forconnecting the valve member 30 the anchoring member. Primarily, stents60, 62 capture the ring 32 of the valve member 30 therebetween simply byproviding upper and lower barriers to movement. The valve member 30 isdesirably a non-expandable type, therefore the ring 32 is not overlysusceptible to compression. By providing sufficient of the thickness ofthe stents 60, 62, the valve member 30 remains sandwiched therebetween.In this regard, the outflow end of the first stent 60 and the inflow endof the upper stent 62 are preferably flat or blunt so as not to dig intothe ring 32. Because of the anchoring function of the stents 60, 62,there is no need to suture the valve member 30, and thus the ring 32 maybe made relatively firm or rigid. Alternatively, the facing edges of thestents 60, 62 may be provided with barbs or other such piercing devices,and the ring 32 provided as a conventional suture-permeable sewing ring.

As noted above, the anchoring members or stents described herein couldinclude barbs or other anchors to further secure the stent to thetissue. Further, the barbs could be deployable (e.g., configured toextend or be pushed radially outward) by the expansion of a balloon.Likewise, the stent can be covered to promote in-growth and/or to reduceparavalvular leakage. The cover would be similar to those on othervalves, e.g., a Dacron tube or the like.

Alternatively, the valve member may be constructed with a tubular frameor cage for engaging one or both stents 60, 62. In various preferredembodiments, the stents may be self-expanding or balloon-expandable. Inone advantageous feature, the valve member 30 of this embodiment is notrequired to be mounted within a cylindrical frame or stent. Accordingly,the flow through area of the valve member may be maximized to improvevalve function. In another variation, the first and second stents may beintegrated as a single unit forming a chamber therebetween. In thisvariation, the valve member may be expanded within the chamber forsecurely deploying the valve member in the body channel.

With reference now to FIG. 8, another alternative embodiment of atwo-stage prosthetic valve 10E is illustrated wherein the anchoringmember or stent 70 is provided with a varying diameter. Moreparticularly, a lower portion 72 of the stent has a small diameter sizedfor implantation at a native valve annulus. In one preferredconfiguration, the small diameter is about 23 mm. The stent also has anupper portion 74 with a larger diameter for receiving an expandablevalve member 30A. In one preferred configuration, the larger diameter isabout 29 mm. In this embodiment, the valve member 30A is provided as atubular body that is radially expandable. The valve leaflets aredisposed along the interior of the valve member.

The stent 70 preferably includes a circular ridge 76 formed along thetransition region between the large and small diameters. The ridgeprovides a seat for the base of the valve member 30A. In one preferredembodiment, the ridge 76 incorporates a support wire 78 that extends atleast partially through the ridge for strength and may be used toprovide a radiopaque marker. The remaining portion of the ridge may beformed of Dacron or any other suitable material. The stent 70 may becomprised of a screen or mesh. A cover 75, such as a polymer sheet, maybe provided along at least a portion of the stent to help preventleakage and enhance sealing. In addition, a sponge or cloth may beprovided along the exterior portion of the stent for further enhancingsealing.

The stent 70 of FIG. 8 may be self-expanding or balloon-expandable. Whenprovided as a balloon-expandable stent, a expandable tapered (i.e., twodiameter) balloon may be provided for deploying the stent. Whenconfigured for use with a stent having diameters of 23 mm and 29 mm, theballoon may have diameters of 22 mm and 28 mm, respectively.

With reference now to FIGS. 9A and 9B, another alternative embodiment ofa component prosthetic valve 10F is provided wherein a valve member 30is configured for connection with an anchoring member or stent 90. Inthis embodiment, the stent 90 is provided with a groove 94 formed in aninwardly-directed circumferential member 92. The groove extends at leastpartially around the inner portion of the stent and is sized to receivethe ring portion 32 of the valve member 30. In one preferred embodiment,the ring is configured to snap fit into the groove, as seen in FIG. 9B.In another variation, the ring is made of a shape memory materialconfigured to expand after deployment in the body. In this variation,the ring is configured to radially expand for securely anchoring itselfwithin the groove.

With reference now to FIG. 10, yet another alternative embodiment of acomponent prosthetic valve 10G is illustrated wherein the valve member30 is configured for threadable engagement with an anchoring member orstent 100. In this embodiment, the stent is provided on one end with athreaded region 102 along an inner wall configured for receiving athreaded flange portion 33 on the valve member 30. The threaded flangeportion is preferably provided along the ring 32 at the base of thevalve member. During use, the stent is first deployed in the bodychannel. The stent may be deployed in a manner wherein the diameter ofthe threaded region remains substantially constant so as to not affectthe threads. In one embodiment, the stent is substantiallynon-expandable and is delivered into the lumen in its fully expandedcondition. This can be achieved by first stretching or dilating thedelivery site for receiving the stent. In another embodiment, only thelower portion of the stent is expanded for engaging the tissue. Ineither embodiment, the valve member is threadably attached to thethreaded flange on the stent after the stent has been firmly anchored inthe body channel. This attachment means is configured such that thevalve member advantageously connects to the stent through rotationalmovement. Accordingly, longitudinal forces applied to the valve memberafter implantation will have little or no effect on the integrity of theconnection between the stent and valve.

With reference now to FIG. 11, an alternative prosthetic heart valve 10Hcomprises a valve member 30, an anchoring member or stent 110, and alocking ring 112. As before, the stent 110 desirably expands first atthe implantation site, after which a conventional valve member 30couples to the stent through the use of the locking ring 112. However,the valve member 30 may also be expandable, and the stent 110 can take avariety of forms. In a preferred embodiment, the stent 110 comprises alatticework of balloon-expandable members adapted to be delivered to theimplantation site in a collapsed or compressed state, and then expandedfrom within using a balloon. Of course, a self-expanding stent 110 couldalso be used, and additional anchoring means of such as exterior barbsmay be provided to help prevent the stent from migrating afterimplantation.

A series of tabs or flanges 114 project slightly inwardly from anoutflow end of the stent 110. The flanges 114 are configured to matewith exterior threading 116 on a downwardly-projecting shoulder of thelocking ring 112. The number and configuration of the flanges 114 isselected to avoid interfering with radial expansion of the stent 110,and also to mate with the threads 116 of the locking ring 112.Desirably, a series of space-apart flanges 114, for example eight,evenly spaced around the outflow rim of the stent 110 project inwardtherefrom a distance of between 1-3 mm.

An inner bore 118 of the locking ring 112 possesses a diameter largeenough to pass over the entire valve member 30 except for the base ring32, which could be a sewing ring of a conventional heart valve. Whencoupled together, the locking ring 112 surrounds the valve member 30 anddesirably includes an inner ledge that rests on the base ring 32thereof. The inner diameter of the shoulder having the exteriorthreading 116 is sized larger than the base ring 32 and extendsdownwardly into engagement with the flanges 114. By screwing down thelocking ring 112, the components can be easily and rapidly assembled.After implantation, removal and replacement of the valve member 30merely requires releasing the locking ring 112 from any tissue ingrowth,unscrewing and removing it, and releasing the valve member 30 from thestent 110 by cutting away any tissue ingrowth therebetween.

FIGS. 12A and 12B illustrate another prosthetic heart valve 10I of thepresent invention having an expandable anchoring member or stent 120coupled to a valve member 30. Much like the valve 10A of FIGS. 3 and 4,the outflow end of the stent 120 exhibits a series of spaced-apart tabs122 that curl around the base ring 32 of the valve member 30. In thisembodiment, the stent 120 is a straight tube, and there are fewer tabs122 (e.g., eight) than there are tines 46 in the valve 10A. The tabs 122may be bent using an auxiliary tool (not shown), or may possess aproperty permitting autonomous bending, such as temperature-inducedmovement.

FIGS. 12C and 12D are sectional views through one side of the prostheticheart valve 10I of FIG. 12B schematically illustrating an exemplary toolthat may be used to bend the tabs 122 on the outflow end of the stent120 around the base ring 32 of the valve member 30. It should be notedthat the section is taken radially through one side of the system, andthe tool will typically be annular or at least peripherally arranged tobend each one of the tabs 122. The tool comprises a forming member 124having a forming surface 125. The forming member 124 slides within andrelative to an outer anvil 126 having an inwardly angled portion 128that directly surrounds and engages each of the tabs 122. The formingsurface 125 is curved such that axial displacement of the forming member124 in the direction shown in FIG. 12C curls each of the tabs 122 inwardto the shape of FIG. 12D. In this embodiment, the tabs 122 wrap over thetop of and restrain the base ring 32. In other embodiments, the tool maybe used to bend prongs so that they pierce the base ring 32. It shouldbe noted that the outer anvil 126 is primarily used for centeringpurposes to guide the forming member 124 toward the tabs 122.

FIGS. 13A and 13B illustrate another embodiment of a prosthetic valve10J having multiple components joined together. An anchoring member orstent 130 includes a plurality of tangs or flanges 132 on an outflowend. A valve member 30 seats adjacent the outflow end of the stent 130,and a fixation ring 134 extends therearound. Additionally, a pluralityof tabs 136 project downward from the fixation ring 34. Although notshown, the tabs 136 enable the fixation ring 34 to be coupled to thebase ring 32 of the valve member 30 by mechanically bending the tabs, orconfiguring the tabs to curl upon reaching a certain temperature. Asseen in FIG. 13B, the flanges 132 extend around the outside of thefixation ring 134 and bend around the upper or outflow end thereof.Again, this can be accomplished using an auxiliary tool or throughtemperature-induced movement. Alternatively, the flanges 132 may beformed of a resilient polymer or metal having the shape seen in FIG. 13Bsuch that they can be flexed outward around the fixation ring 134 andthen snapped back into place to secure the ring around the valve member30. Although not shown, the interior of the fixation ring 134 isdesirably contoured to mate with the base ring 32 of the valve member30. The fixation ring 134 can be made of any number of materials,including rigid, flexible, metallic, polymer, bioabsorbable, etc. Onepreferred configuration is a Teflon ring coated with anti-thrombogenicor anti-microbial compositions.

FIG. 14A illustrates a still further prosthetic heart valve 10K havingan expandable anchoring member or stent 140, a valve member 30, and awireform-shaped adapter 142. The stent 140 and valve member 30 have beenpreviously described. The adapter 142 has a shape similar to a so-called“wireform” used in the internal construction of many prior artbioprosthetic tissue valves. Indeed, the valve member 30 is desirably aCarpentier-Edwards PERIMOUNT Magna® Aortic Heart Valve made by EdwardsLifesciences, and including therewithin an Elgiloy wireform. The adapter142 may be formed of biocompatible polymers or metals, preferably analloy such as Nitinol.

The adapter 142 carries a plurality of securing tabs 144, 146. In theillustrated embodiment, three lower securing tabs 144 are located at theapex of the three cusps of the wireform-shape, and two upper securingtabs 146 are located at each of the upstanding commissures of thewireform-shape, for a total of six at the commissures. FIG. 14B is adetailed illustration of the assembly of the stent 140, valve member 30,and adapter 142. The base ring 32 of the valve member 30 seats on orjust within the outflow end of the stent 140, and the adapter 142 fitsover the valve member and couples to it, as well as to the stent. Inthis regard, the cusps of the adapter 142 seat on or slightly outsidethe base ring 32 with the commissures surrounding and conforming to thecommissures of the valve member 30. The cusp securing tabs 144 bend upover the base ring 32 and down into engagement with the stent 140. Thetwo securing tabs 146 at each commissure of the adapter 142 bend or wraparound the corresponding valve member commissure.

Again, a supplemental tool may be used to accomplish the bending of thesecuring members 144, 146, or they may exhibit temperature-changingproperties. In the illustrated embodiment, the securing tabs 144, 146are malleable, though other configurations are within the scope of theinvention. For example, the lower securing tabs 144 may be barbs ortangs which pierce the base ring 32 and hook around the stent 140, whilethe upper securing tabs 146 may be resilient straps that wrap aroundeach one of the commissures of the valve member 30.

To further secure the valve member 30 to the stent 140, the stentincludes a plurality of upstanding barbs 147 comprising spaced apartposts having teeth 140. The adapter 142 possesses a plurality ofoutwardly projecting brackets 149 defining slots therethrough. As seenin FIG. 14B, the barbs 147 pass through the base ring 32 and through theslots of the brackets 149 in the adapter 142. The teeth 148 preventremoval of the barbs 147 from the slots. In this way, the stent 140 andadapter 142 are securely connected together, sandwiching the valvemember 30 therebetween.

Another possibility is that the securing tabs 144, 146 are not initiallycarried by the adapter 142, but instead are added after the assembly ofthe three components. For instance, staples or even sutures may be usedafter the valve member 30 seats on the stent 140, and the adapter 142 islowered around the valve member. Even if sutures are used, the timerequired relative to a conventional sewing operation is greatly reduced.Moreover, the structural support and anchoring properties of thewireform-shaped adapter 142 greatly enhances the overall integrity ofthe assembly. In this regard, securing tabs such as those shown may beplaced more continuously around the adapter 142 so as to provide moreuniform contact with the valve member 30. One possible configuration isa series of small hooks or brackets extending along the undulatingadapter 142 that loop over the corresponding undulating shape on thevalve member 30. The valve member 30 is therefore restrained from upwardmovement relative to the adapter simply by lowering the adapter 142 overthe valve member. In such an arrangement, only the lower securingmembers need be actively attached, such as by causing their shape tochange and bend into engagement with the stent 140, as seen in FIG. 14B.

A further prosthetic valve embodiment 10L seen in FIG. 15A includes anexpandable anchoring member or stent 150 and a valve member 30. Aplurality of fixation straps 152 ring the outflow end of the stent 150.Four such straps 152 are shown, but more or less made be utilized. Forexample, three straps extending farther around the periphery of theoutflow end of the stent 150 may be substituted. Conversely, four ormore straps that overlap one another may be used.

FIG. 15B illustrates the valve member 30 seated on top of the stent 150with one of the straps 152 securing the two components together. Straps152 may be attached at both of their ends to the stent 150, and maycomprise a resilient biocompatible material that stretches over the basering 32 of the valve member 30. Alternatively, the straps may be bent orfolded over the base ring. In one variation, one end of each strap 152may be initially free, and after the strap is looped over the base ring32 is then attached to the stent 150, somewhat like a beltconfiguration. The straps 152 may be formed of a variety of materials,typically cloth-covered so as to permit tissue ingrowth over acloth-covered base ring 32 for enhanced long-term anchorage. Onepossible variation is to incorporate small barbs or Velcro-style hooksin each of the straps 152 so as to gain better purchase on the base ring32.

FIGS. 16A and 16B illustrate a still further embodiment, wherein theprosthetic heart valve 10M comprises a valve member 30, expandableanchoring member or stent 160, and coupling ring 162. The coupling ring162 defines a series of circumferentially-spaced apertures or slots 164that receive upstanding hooks or latches 166 on the stent 160. As seenin FIG. 16B, the coupling ring 162 surrounds the commissures of thevalve member 30 and seats on the base ring 32, and the latches 166extend through the slots 164 and are secured therein by outwardlydirected teeth 168. In the illustrated embodiment, the latches 166 eachcomprise a pair of parallel, spaced apart upstanding members, each withan outwardly directed tooth 168, which may be cammed inward toward oneanother as they pass through the slots 164. As the teeth 168 clear theslot 164, the parallel members resiliently spring outward thus latchingthe stent 160 to the coupling ring 162. The coupling ring 162 mayfurther include a plurality of outwardly projecting tabs 172 that arebent or curl around the base ring 32.

To aid in guiding the latches 166 through the slots 164, one or moreguide members may be used to direct the coupling ring toward the stentsuch that the slots are aligned with the latch members. For example, inthe illustrated embodiment, a plurality of guide filaments 170 areattached to each one of the upstanding latch members and passed throughthe corresponding slots. FIG. 16A illustrates the pre-assembled valve10M with the guide filaments 170 extending up through each of the slots164. The implantation procedure comprises first delivering and expandingthe stent 160, and then advancing the valve member 30 to the positionshown in FIG. 16B. The coupling ring 162 is then parachuted down thearray of guide filaments 170, ultimately facilitating passage of thelatches 166 through the slots 164. The final assembly is seen in FIG.16B. in a preferred embodiment, each two guide filaments 170 comprises astrand of a single looped passing through small holes in each of thelatch members. Removal of the guide filaments 170 is thus a simplematter of just pulling one of the strands, or severing the loop inbetween the latch members. Note that guide filaments could be used onany of the embodiments described herein to facilitate coupling of theseparate components of the prosthetic heart valves. For example, inanother variation, a wireform similar to the embodiment illustrated inFIG. 14A may also be used with a guiding filament.

The exemplary embodiment shows the latches 166 extending around theoutside of the base ring 32 of the valve member 30. It is entirelyfeasible, on the other hand, to design the latches 166 to pierce throughthe base ring 32. Inclusion of the coupling ring 162 is suggested,because of its washer-like function in holding the assembly together.However, the latches 166 may be designed to pierce through and securelyfasten to stent 160 to the base ring 32 without the use of the couplingring 162. In this regard, the latches 166 may be configured differently,or more than the number shown may be provided. For example, 4, 6, 8, ormore single latch members having a configuration such as shown with aleading sharp point and rearwardly directed barb (much like a fish hook)could fight adequate anchorage through a conventional base ring 32 madeof a silicone sponge covered with cloth. Those of skill in the art willunderstand that there are numerous alternatives available.

The stent 160 in FIGS. 16A and 16B has an outflow end that is preferablysized larger than its inflow end. More particularly, the outflow end isflared so as to receive therein the base ring 32 of the valve member 30.In this way, a larger orifice valve member can be utilized than with astraight tubular stent. The reader is also reminded that at least theflared portion of the stent 160 is desirably provided with a sleeve ofDacron or other such fabric to help prevent paravalvular leaking betweenthe base ring 32 and the surrounding native valve annulus.

With reference to FIGS. 17A and 17B, yet another two part prostheticvalve 10N is configured for rapid deployment in a heart for replacing adefective native valve. In this version, an expandable anchoring memberor stent 180 couples to a valve member 30 through the use of a couplingring 182 in a manner similar to the last-described embodiment. Thecoupling ring 182 carries a plurality of latches 184 which mate withbrackets 186 provided on the stent 180. In the illustrated embodiment,the latches 184 again comprise a pair of spaced-apart latch membershaving outwardly directed teeth 188, and the brackets 186 are simplyapertures or slots in material loops that extend outward from the stent180 adjacent its outflow end. Bringing the three components together,the latches 184 extend through the brackets 186 as seen in FIG. 17B. Tofacilitate proper and rapid passage of the latches 184 through thebrackets 186, a plurality of guide filaments 190 loop through thebrackets 186 and through holes provided in the latches 184. Simplyparachuting the coupling ring 182 down the filaments 190 aims thelatches 184 through the brackets 186.

At this stage, it is important to note that any of the fixation rings(i.e., locking ring 112, fixation ring 134, adapter 142, coupling ring162, or coupling ring 182) described above could be designed to engagethe surrounding tissue (annulus) and provide additional protection againparavalvular leakage. For example, a tissue growth factor or fibrin glueor the like may be coated on the exterior of any of these fixation ringsfor a better seal. Alternatively, the fixation rings might have an outerrim of fabric for encouraging tissue ingrowth. Moreover, the variousfixation rings described and the base ring 32 of the valve member 32 maybe constructed as a single component. For example, the base ring 32could be configured to have slots (or any coupling member) in lieu of aseparate fixation ring.

With reference now to FIG. 18, an alternative expandable anchoringmember or stent 200 is illustrated wherein the anchoring member isconfigured to receive a valve member 30 to form a prosthetic heartvalve. As illustrated in FIG. 19, a portion of the valve member isgripped between inwardly extending members located within the stent.More particularly, the stent 200 comprises a plurality of axial struts202 connected by a number of rows of circumferential crown-shaped struts204 to form a generally tubular structure. A lower or inflow end of thestent 200 includes a circumferential row of crown-shaped struts 206 thatis larger than the others such that the inflow end of the stent flaresoutward. The upper rows 204 of circumferential struts define valleys(pointing downward) at the axial struts 202 and peaks (pointing upward)midway between each two adjacent axial struts. As seen from FIG. 18,therefore, the spaces defined between adjacent axial struts 202 andadjacent rows of circumferential struts 204 are preferablychevron-shaped, pointed upward. Conversely, the lower circumferentialrow of struts 206 has upper peaks at the axial struts 202 and lowervalleys therebetween, resulting in elongated hexagon-shaped spacesbetween the lower two circumferential rows of struts.

The stent 200 possesses a plurality of prongs that extend inwardtherefrom to capture the valve member 30. As seen in FIG. 19, the basering 32 of the valve member 30 seats on a plurality of lower prongs 208.FIG. 18 shows the lower prongs 208 extending inward from the lower rowof struts 206 at the valleys between adjacent axial struts 202. Thelower prongs 208 terminate in enlarged heads 210 to prevent damage tothe base ring 32. As seen in FIG. 19, the lower prongs 208 projectinward farther than the expanded to defined by the upper portion of thestent 200. Additionally, a plurality of upper prongs 212 extend inwardfrom one of the upper rows of circumferential struts 204. In theillustrated embodiment, there are four rows of circumferential struts204, and the upper prongs 212 project inward from the second lowest row.As seen in FIG. 19, the upper prongs 212 contact the base ring 32 of thevalve member 30. In this manner, the valve member 30 is captured betweenthe lower prongs 208 and upper prongs 212.

In the illustrated embodiment, the stent 200 includes twelve axialstruts 202, and one of each of the prongs 208, 212 between each adjacentpair of axial struts, resulting in twelve each of the lower and upperprongs. Of course, the number of prongs could be more or less dependingon the configuration of the stent 200. Further, there may be more thanone prong between adjacent pairs of axial struts 202, or the prongs maybe provided only between every other pair. The prongs 208, 212 may beinitially flat within the profile of the surrounding struts to preventinterference with an expansion-balloon. After stent deployment they maybe bent inward into the angles shown using a tool (not shown).Alternatively, the balloon wall could be relatively thick and able towithstand puncture by the round heads of the prongs 208, 212 such thatthey are at all times biased inward and automatically assume the anglesshown after balloon removal.

To deploy the prosthetic heart valve of FIGS. 18 and 19, the useradvances the stent 200 in a collapsed state through the vasculature or achest port into the target implantation site. Through self-expansion orballoon-expansion, the stent 200 expands into contact with thesurrounding valve annulus. The valve member 30 then advances intoposition adjacent the outflow or upper end of the stent 200. Desirably,the valve member 30 is a conventional non-expandable design, but couldalso be expandable, in which case it is then expanded prior to assemblywith the stent 200.

The outer diameter of the base ring 32 of the valve member 30 is sizedapproximately the same as the inner diameter of the tubular upperportion of the stent 200. The valve member 30 advances from the outflowend of the stent 200 toward the inflow end until the base ring 32contacts the circular row of upper prongs 212. The upper prongs 212 areflexible, hinged, or otherwise capable of being displaced outward by thebase ring 32 as the valve member 30 passes. Ultimately, the base ring 32seats on the circular row of relatively non-flexible lower prongs 28 andthe valve member 30 cannot be advanced farther. The spacing between thelower prongs 208 and the upper prongs 212 is such that the upper prongs212 spring inward at the point that the base ring 32 seats on the lowerprongs 208. The upper prongs 212 may be formed with blunt heads like thelower prongs 208, or may be straight or even sharp-pointed to pierce thebase ring 32 and provided enhanced anchorage. In a preferred embodiment,both the lower prongs 208 and upper prongs 212 possess enlarged, bluntheads such that the base ring 32 is merely trapped between the two setsof prongs.

The design of the stent 200 of FIG. 18 thus enables rapid deployment ofa valve member therewithin, as well as positive tactile feedback to theuser with valve member 30 is completely installed. Because the base ring32 is sized closely within the stent 200, good peripheral sealing isprovided. To better enhance sealing, a peripheral skirt or layer ofgraft material may be added on the interior or exterior of the stent200.

With reference to FIG. 20, another embodiment of a prosthetic heartvalve 220 comprises a tubular, expandable anchoring member or stent 222,a valve member 30, and an adapter ring 224 for coupling the twocomponents together. The stent 222 and manner of connecting the stent tothe valve member 30 is similar to embodiment of FIGS. 3 and 4, and alsothe embodiment of FIG. 12, in that a plurality of tines 226 projectupward from the stent 222. However, instead of the tines 226 piercing orcurling around the base ring 32 of the valve member 30, the tinesinteract with the adapter ring 224. In particular, the adapter ring 224attaches around the lower periphery of the base ring 32, preferably viaa secure stitch line formed during assembly of the valve member 30. Thetines 226 pierce or otherwise engage the adapter ring 224 instead of thebase ring 32 to couple the valve member 30 to the stent 222. Thesupplemental adapter ring 224 provides an added margin of safety thathelps prevent damage to the valve member 30 by the tines 226. Forinstance, if the tines 226 are configured to pierce and curl inward,they are farther away from the inner flexible leaflets 36 of the valvemember which are susceptible to puncture or tearing.

With reference to FIG. 21, yet another embodiment of a prosthetic heartvalve 230 comprises an anchoring member or stent 232 coupled to a valvemember 30 via a plurality of sutures 234. The components of the valve230 are shown exploded above a container or jar 236 used to store thecomponents. In this regard, the entire assembly, including theattachment sutures 234, may be stored together in the jar 236 so as tobe ready for deployment. Alternatively, only the stent 232 and valvemember 30 may be stored in the jar 236, and the sutures 234 added justprior to deployment but before the actual operation. Still further, thestent 232 can be stored dry in a sterile container, while the valvemember 30 having bioprosthetic leaflets may be stored separately in asuitable preservative fluid such as glutaraldehyde. In any event,details of the prosthetic heart valve 230 will be described below withreference to FIGS. 22A through 22C.

FIGS. 22A through 22C show the components of the prosthetic heart valve230 in conjunction with a valve dilator/delivery tube 240. The usage ofthe delivery tube 240 will be described below. The stent 232 comprisesan expandable, tubular structure formed of a plurality of axial struts242 joined by a plurality of angled circumferential struts 244. In thisembodiment, there are four rows of circumferential struts 244, the uppertwo pointing upward, and the lower to pointing downward. The result is aseries of both diamond-shaped and chevron-shaped openings. Three axialbars 246 substitute for the more narrow struts 242 at threeevenly-spaced positions around the stent 232. As seen in the view ofFIG. 22B, the commissures 34 of the valve member 30 align with the axialbars 246.

With reference now to the sectional view of FIG. 22C, the stent 232additionally comprises an inner fixation ring 250 and an outer sealingring 252. Both these rings 250, 252 attach to the struts of the stent232 independently, or to each other through the struts. For example, aseries of sutures (not shown) can be used to join the inner ring 250 andouter ring 252 in a relatively continuous circumferential line aroundthe stent 232. These rings are desirably made of suture-permeable,typically compressible material such as silicone rubber, or may berolled up fabric cuffs. In any event, the inner fixation ring 250couples to the valve member 30, while the outer sealing ring 252 helpprevent leakage around the stent 232.

As seen in FIG. 22A, the attachment sutures 234 extend upward within thestent 232 from the inner fixation ring 250. In this regard, each twostrands of the attachment sutures 234 may be defined by looping a singlelength of suture downward and back upward through the fixation ring 250.The circular array of sutures 234 then passes through correspondingsectors of the base ring 32 of the valve member 30. Again, this can bedone at the time of valve assembly, just prior to the valve replacementprocedure, or after the stent 232 has been implanted. Those of skill inthe art will understand the process of lining up the circular array ofattachment sutures 234 into the appropriate locations around the basering 32 to permit the valve member 32 to parachute down the suturesuntil it contacts the fixation ring 250.

The entire procedure will now be described in conjunction with use ofthe valve dilator/delivery tube 240. As mentioned above, the valvereplacement procedures described herein are sometimes done withoutremoving the existing native valve. The annulus and valve leaflets areoften heavily calcified, and sometimes provide a serious impediment topassage and implant of a replacement valve, even a valve that isinitially quite small and balloon expanded. To help widened the orificein which the prosthetic valve 230 will be implanted, the delivery tube240 receives all of the valve components therein and acts as aprotective sleeve and dilator. In a preferred embodiment, just thesealing ring 252 extends out of the delivery tube 240 at an inflow orleading end thereof.

First, the attachment sutures 234 are preinstalled within the fixationring 250 and, while maintaining a non-crossing circular array, arepassed through the delivery tube 240 to be accessible out the upper end.The sutures 234 are then passed through the appropriate locations withinthe base ring 32 of the valve member 30. Of course, this can be doneduring fabrication of the prosthetic heart valve 230, though somestructure for maintaining the relative position and orientation of twocomponents is required. In any event, a holder (not shown) attached tothe valve member 30 is used to advance the valve member along the arrayof sutures 234 and within the delivery tube 240, into the approximateposition seen in FIG. 22A.

When the patient has been prepared, and an access opening to the targetimplantation site created, the assembly of the prosthetic heart valve230 within the delivery tube 240 advances into the body. The leading endcomprises the sealing ring 252 and an outwardly bulged portion 254 inthe delivery tube 240. For installation in the aortic annulus, thedelivery tube 240 advances down the ascending aorta until the stent 232lines up with the annulus (with the help of radiopaque markers or thelike). The outwardly bulged portion 254 in the delivery tube 240 helpsopen up the calcified annulus. Even if the native valve is resected,sometimes the annulus will shrink a little prior to implant of thevalve. The valve dilator/delivery tube 240 thus helps open up theannulus to permit implant of a desired diameter valve. The contour ofthe bulged portion 254 is relatively smooth, and the material may beTeflon or other such highly lubricated surface so that the tube easilyslips through the annulus. A slight back-and-forth movement may berequired to fully open the annulus.

At this stage, the delivery tube 250 retracts relative to the stent 232,through the use of a pusher (not shown) for example, such that the stent232 may fully expand into the annulus. The stent 232 may beself-expanding and thus be only partially expanded within the deliverytube 240. When the delivery tube 240 is removed, the stent 232 springsoutward into firm engagement with the annulus. Alternatively, a balloon(not shown) may be used to accomplish the final expansion of the stent232, which configuration would require a catheter passing through thecenter of the valve leaflets 34. If the stent 232 is balloon expandable,consideration must be taken of the continual attachment of the valve tothe guide sutures 234. On the other hand, if the stent 232 isself-expanding, then typically an auxiliary sheath would be provided tohold the stent in the contracted condition.

When the user is satisfied that the stent 232 is properly positioned,the valve member 30 is advanced using the aforementioned holder (notshown). As the valve member 30 advances, care is taken to ensure thatthe attachment sutures 234 remain untangled and taut. Ultimately, thevalve member 30 seats on the fixation ring 250 as seen in FIGS. 22B and22C. At this point, the user ties off and severs the attachment sutures234 in a conventional manner. The provision of the sealing ring 252directly adjacent and surrounding the fixation ring 250 greatly enhancesthe ability of the prosthetic valve 230 to resist paravalvular leaking.

In one advantageous feature, preferred embodiments of the componentbased prosthetic valves described herein may be used with existingtechnology. For example, certain stent embodiments may be configured forattachment to sewing rings provided on existing prosthetic valves. Inother cases, valve member require only small variations in order to beused with the component based system. Not only will this contribute to alower price for the final valve, but also learned familiarity to thesystem for surgeons who might be hesitant to adopt a completely newsystem.

It will be appreciated by those skilled in the art that embodiments ofthe present invention provide important new devices and methods whereina valve may be securely anchored to a body lumen in a quick andefficient manner. Embodiments of the present invention provide a meansfor implanting a prosthetic valve in a surgical procedure withoutrequiring the surgeon to suture the valve to the tissue. Accordingly,the surgical procedure time is substantially decreased. Furthermore, inaddition to providing an anchoring member for the valve, the stent maybe used to maintain the native valve in a dilated condition. As aresult, it is not necessary for the surgeon to remove the nativeleaflets, thereby further reducing the procedure time.

It will also be appreciated that the present invention provides animproved system wherein a valve member may be replaced in a more quickand efficient manner. More particularly, it is not necessary to cut anysutures in order to remove the valve. Rather, the valve member may bedisconnected from the stent (or other support structure) and a new valvemember may be connected in its place. This is an important advantagewhen using biological tissue valves or other valves having limiteddesign lives. Still further, it will be appreciated that the devices andmethods of the present invention may be configured for use in aminimally invasive approach (e.g., through a small incision between theribs) or in a percutaneous procedure while still remaining within thescope of the invention.

While the invention has been described in its preferred embodiments, itis to be understood that the words which have been used are words ofdescription and not of limitation. Therefore, changes may be made withinthe appended claims without departing from the true scope of theinvention.

What is claimed is:
 1. A replacement prosthetic heart valve, comprising:an expandable anchoring member sized to contact a heart valve annulus inan expanded state and defining a lumen having an inner diameter, theanchoring member having a circular cross-section and a length such thatthe anchoring member may be expanded within a native valve annulus tothe push aside valvular leaflets of the native valve; and a one-wayvalve member comprising a non-expandable/non-collapsible support frameand defining an exterior dimension sized to fit within the lumen of theanchoring member, the valve member and anchoring member being configuredto engage each other and hold the valve member within the lumen.
 2. Theheart valve of claim 1, wherein the anchoring member comprises a stenthaving a wider outflow end than an inflow end, and wherein the valvemember comprises a base ring surrounding an inflow end thereof, the basering being sized to fit within the outflow end of the stent.
 3. Theheart valve of claim 2, wherein the anchoring member further has acircular ridge formed along a transition region between the wideroutflow end and inflow end, the ridge being smaller than the valvemember exterior dimension so that the valve member seats on the ridge.4. The heart valve of claim 3, wherein the ridge incorporates a supportwire for strength.
 5. The heart valve of claim 4, wherein the supportwire has a radiopaque marker.
 6. The heart valve of claim 1, wherein theanchoring member is provided with a groove formed in aninwardly-directed circumferential member that extends at least partiallyaround the lumen of the anchoring member and is sized to receive a ringportion of the valve member.
 7. The heart valve of claim 6, wherein thevalve member comprises a non-expandable support frame from which thering portion extends, and the ring portion forms a snap-fit with thegroove.
 8. The heart valve of claim 6, wherein the ring portion isconfigured to expand into the groove after deployment within theanchoring member.
 9. The heart valve of claim 1, wherein the valvemember comprises a peripheral ring portion and the anchoring member hasa plurality of prongs that extend inward therefrom into the lumen tocapture the ring portion of the valve member.
 10. The heart valve ofclaim 9, wherein there are two rows of spaced-apart prongs that are eachangled inward and toward the other row of prongs, and wherein the prongsare flexible to permit passage of the ring portion of the valve memberinto the space between the rows.
 11. The heart valve of claim 10,wherein each of the prongs terminates in an enlarged head to preventdamage to the base ring.
 12. The heart valve of claim 1, wherein theanchoring member comprises an outer sealing ring to help prevent leakagearound the anchoring member.
 13. The heart valve of claim 12, whereinthe valve member includes a suture-permeable base ring surrounding aninflow end thereof, and the anchoring member comprises asuture-permeable fixation ring attached within the lumen.
 14. The heartvalve of claim 13, wherein the valve member connects to the anchoringmember via sutures looped between the base ring and the fixation ring.15. The heart valve of claim 1, wherein the valve member includes asuture-permeable base ring surrounding an inflow end thereof, and theanchoring member comprises a suture-permeable fixation ring attachedwithin the lumen, wherein the valve member connects to the anchoringmember via sutures looped between the base ring and the fixation ring.16. The heart valve of claim 15, wherein the base ring and the fixationring comprise silicone rubber.
 17. The heart valve of claim 15, whereinthe base ring and the fixation ring comprise rolled up fabric cuffs. 18.The heart valve of claim 1, wherein the support frame defines aplurality of alternating cusps and upstanding commissures that supportflexible leaflets.
 19. The heart valve of claim 18, wherein the flexibleleaflets are bovine pericardial leaflets.
 20. The heart valve of claim1, wherein the valve member is configured to be detached from within theanchoring member while implanted and replaced with another valve member.